We design a distributed platform with blockchain as a system service for supporting transaction execution in insurance processes. The insurance industry is heavily dependent on multiple processes between transacting parties for initiating, maintaining and closing diverse kind of policies. Transaction processing time, payment settlement time and security protection of the process execution are majo...
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Blockchain technology and the application of smart contracts allow for automation of verifiable digital processes between any number of parties. The Internet of Things (IoT) has seen great potential in the past decade to revolutionise our day-to-day lives with the aim of automating physical processes by incorporating Internet-connected devices into commodities. By integrating the IoT with blockcha...
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Nowadays, vehicles odometer fraud is becoming a growing problem internationally, and is costing European consumers between 5.6 to 9.6 billion euros per year. This is partly due to the lack of unified vehicles life-cycle management, and to the fact that vehicles data are currently spread across multiple stakeholders that do not trust each other or collaborate together. In this paper, we propose a B...
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Cooperative Intelligent Transportation System (C- ITS) enables inter-networking of vehicles for alerts exchanging in order to improve road safety. While this technology is about to enter the market in the upcoming years, critical questions related to the communication security continue to be challenging research concerns. Current solutions to secure inter-vehicle communication depend mainly on the...
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Blockchains have revolutionized the storage of data in an immutable, transparent and non-centralized way. However, public blockchain systems like the Bitcoin system face a problem of scalability, primarily due to the significant and growing size of its blockchain. This paper introduces a method, termed block summarization, which reduces blockchain storage overhead for systems having transferable t...
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As proof-of-work blockchains are inherently energy greedy and offer probabilistic guarantees, blockchains based on Byzantine consensus appear as a promising technology to track billions of connected devices. In this paper, we evaluate the performance of prominent blockchains that solve the classic Byzantine consensus problem. Our results show that while offering reasonable throughput their perform...
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Blockchain technology has attracted increasing attention in recent years. One reason of this new trend is the introduction of on-chain smart contracts enabling the implementation of decentralized applications in trust-less environments. Along with its adoption, attacks exploiting smart contract vulnerabilities are inevitably growing. To counter these attacks and avoid breaches, several approaches ...
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The possibility of in-store payments would further increase the potential usefulness of cryptocurrencies. However, this would require much faster transaction verification than current solutions provide (one hour for Bitcoin) since customers are likely not prepared to wait a very long time for their purchase to be accepted by a store. We propose a solution for enabling in-store payments with waitin...
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Real-world smart contracts which preserve the privacy of both, their users and their data, have barely been proposed theoretically, let alone been implemented practically. In this paper, we are the first to implement a privacy-preserving protocol from the energy domain as a smart contract in Ethereum. We elaborate on and present our implementation as well as our practical findings, including more ...
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Blockchains, such as Bitcoin and Ethereum and their respective P2P networks have seen significant adoption in many sectors in the past few years. All these technologies that use the Blockchain pattern show that it is possible to rebuild any transactional system with better performance without relying on any trusted parties to manage transactions between peers. This insight has lead many companies ...
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One of the most popular platform based on blockchain technology is Ethereum. Internal activity on this public blockchain is analyzed both from a quantitative and qualitative point of view. In a first part, it is shown that the creation of the Ethereum Alliance consortium has been a game changer in the use of the technology. In a second part, the network robustness against attacks is investigated f...
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In this work we propose a compression method for smart contracts deployed in the Ethereum blockchain. By taking advantage of the repetition of sections of bytecode among multiple smart contracts previously deployed in the Ethereum blockchain we propose a new pseudo opcode that acts as a pointer that will allow smart contracts to reuse previously deployed code. We show that our proposed algorithm a...
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Currently, Bitcoin and Ethereum are the two most popular cryptocurrency systems, especially Ethereum. It permits complex financial transactions or rules through scripts, which is called smart contracts. Since Ethereum smart contracts hold millions of dollars, their execution correctness is crucial against attacks which aim at stealing the assets. In this paper, we proposed a security assurance met...
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The design of a successful distributed system for enabling payments and small transactions among Internet users has long been a major challenge in applied computer science. Bitcoin, the first cryptocurrency having reached world-wide popularity, suffers from sustainability problems such as inefficient energy expenditure for its network operation and from perverse incentives that foster speculative ...
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Enterprises have paid attention to blockchain (BC), recently permissioned BC characterized with smart-contract, where business transactions among inter-authorized companies (forming consortium) can automatically be executed based on distributed consensus protocol over user-defined business logics pre-built with program codes. A single BC system will be built across multiple management domains havi...
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